Electric welding machine



G. F. STRONG Feb. 9, 1943.

ELECTRIC WELDING MACHINE Filed April 11, 1941 2 Sheets-Sheet l Zhwentor George E Strong W (Ittorneg Feb. 9, 1943. G. F. STRONG ELECTRIC WELDING MACHINE Filed April 11, 1941 2 Sheets-Sheet 2 -witha Patented Feb. 9, 1943 UNITED STATES PATENT OFFICE ELECTRIC WELDING MACHINE George F. Strong, Grosse Pointe Farms, Mich. Application April 11, 1941, Serial No. 388,051

1 Claim.

This invention relates to electric welding machines and particularly spot welding machines,

An object of the invention is to provide an improved and simplified means for electrically actuating an electrode to and from the work and for pressing it firmly against the work.

Another object is to actuate a reciprocatory electrode to its welding position through a linkage serving to largely multiply pressure derived from an electrical energizing means.

A further object is to provide a simple adjustment for said pressure-multiplying actuating mechanism, that will permit application of the same electrode of work.

These and various other objects are attained by the construction hereinafter described and illus trated in the accompanying drawings, wherein:

Fig. 1 is a side view of a spot welding machine, 7 portion thereof broken away to show an electrode actuating mechanism, the actuated electrode being shown in raised or idle position. Fig. 2 is a view of said mechanism, showing the electrode in lowered or welding position.

In these views, the reference character I designates a hollow frame, having a forwardly project ing upper portion 2 and carrying a forwardly projecting bracket 3, downwardly spaced from the portion 2. Fixed on the front end portion of the bracket 2 is a holder 4 for an upwardly projecting electrode 5. and a coacting electrode 6 projects downwardly from a holder 1 secured by a shank 8 on the lower end of a plunger 9. Said plunger is vertically slidable in a bearing ID integrally depending from the frame portion 2, and a bolt II set into said bearing terminally engages in a key-way l2 of the plunger to prevent its rotation.

The top of the frame projection 2 is formed with a bearing It in which a head It is siidingly adjustable to and from the plunger 9, said head and plunger being connected by a pair of toggle links I! interconnected at l6. Said links are prevented from swinging beyond alignment by an adjustable stop Ila formed by a screw mounted in the front wall of the frame portion 2 and positioned to engage one of the links. The head H is restrained from rotation by the key-forming end of a bolt I1, engaged in a key-way it of said head. Rotative in the top portion of the hearing I! is a shaft is, projecting above said bearing to receive an actuating hand wheel 20. the lower portion of said shaft forming a feed screw 2| en- I 8ed in the head It to adjust it vertically.

I'br applying pressure to the links II. a thrust link 22 extends from the interconnection It to a lever 22 having a lower end fulcrumed on a bracket 24 and its upper end pivotally engaged pressure to different thicknesses and forwardly actuable by the slide bar 25 of a.

inductively or electro-magnetically effect lengthwise travel of a bar under considerable force. It is preferred to pivot the recipromotor upon an underlying bracket 21, thus allowing the motor to adjust itself to swinging of the lever 23. A coiled spring 28 connected to the rear end of the reciprocating bar 25 holds the same normally retracted and thus normally maintains a raised position of the plunger 9 and electrode 6.

Preferably the frame I serves as a housing for a transformer 29 supplying current to the electrode 8 through a flexible cable 30 and to the electrode I through a conductor 3 l In use of the described machine, the operator closes the circuit of the recipromotor 26, after disposing work 32 in a desired position of engagement with the lower electrode. The bar 25 is immediately thrust forward and acts through the lever 23 and link 22 to shift the toggle links into substantial alignment, thus forcing the plunger 9 downwardly. The head I 4 has been previously 'so adjusted that electrode 6 engages the work to strongly press the electrode against the work.

Upon completion of each spot weld, the recipromotor circuit is broken, and spring 28 raises the electrode 8. The quick response of the described mechanism to its electrical control permits a row of spot welds to be produced at maximum speed.

Rotation of the hand wheel 2!! permits the mounting for the upper end of the toggle linkage to be quickly and accurately adjusted up or down to suit different thicknesses of work.

Commercial recipromotors particularly lend themselves to the purpose herein disclosed, because they are compact, capable of exerting a powerful thrust, and may be easily regulated to increase or diminish such thrust.

What I claim is:

In a toggle mechanism, the combination with a pair of toggle links having pivotally joined ends,

of an anchorage .member pivotally mounting the swinging of thearm.

GEORGE F. STRONG. 

